In the slide-fastener field a stringer generally comprises a pair of support tapes to which coupling elements are applied along confronting edges, these coupling elements having a multiplicity of coupling heads which interdigitate upon movement of a slider along the rows of coupling heads. The coupling heads may be individual members clamped upon or molded on the respective edge of the tape or can form part of a continuous coupling element in the form of a coil or meander which is also affixed to the tape, e.g. by being woven or knitted in place or being held in place by rows of stitching with or without textile or other beads or strands which can also extend through continuous coupling elements.
Slide-fastener stringers can be of the closed type or of the separable type. In the closed-type of stringers, the coupling elements at least at one end of the slider path are joined together by an end-stop member which can have a U-configuration and can bridge the two tapes or slide fastener halves. In fully or partially separable slide-fastener stringers, one or both ends of each stringer half can be formed with an end-stop member intended to block withdrawal of the slider. Other end-stop members have been used, e.g. with a plug-and-socket configuration, to allow insertion of one end of a stringer half into a slider positioned by the end-stop member on the corresponding end of the other stringer half so that movement of the slider can then bring about interdigitation of the coupling heads.
Thus it will be apparent that, especially for slide-fastener stringers, end-stop members of various sizes and configurations may be required.
In early slide-fastener stringers, such end-stop members were almost invariably composed of metal, e.g. stamped with a U-configuration so that the legs of the U could be clamped or clenched about the edge of the tape. More recently slide fastener stringers have made use of coupling heads composed of synthetic resin material and it is frequently desirable to provide end-stop members which also are composed of synthetic resin material, especially thermoplastics, and formed by molding.
It is known to produce molded articles utilizing a forming wheel which is provided with spaced-apart beds, each of which can cooperate with an opening in an endless forming band to define a mold cavity when the band is fed to the periphery of the wheel. As the wheel continues to rotate, the mold cavity is brought into registry with a source of the synthetic resin, e.g. injection molding head, and upon hardening of the synthetic resin within the mold cavity the article is drawn away from the bed as the band leaves the periphery of the wheel to enable the articles to be recovered.
In apparatus of this type the band passes around at least one roller spaced from the wheel, meets the wheel tangentially, is slung around a portion of the wheel, and leaves the wheel tangentially to return to the roller in its closed path.
It is frequently desirable to provide small synthetic resin articles of the aforedescribed type which have overhanging portions, i.e. which are molded at least in part around a core. With prior art techniques and the aforementioned band-and-wheel arrangement it has generally not been possible to produce molded articles of such shapes because the articles could not be released from the band.
It has been proposed to solve the problem in part by molding the articles around cords or strands which are fed between the band and the wheel so that the articles are drawn out of the beds by such strands rather than by the band itself. While this technique is advantageous if the articles and the strand must remain together for further processing, the technique is undesirable if separation of the articles from the strand may be required.
In another technique, the band and/or the wheel are designed to form the articles so that they are bridged by synthetic resin webs or strips, e.g. in a ladder arrangement. This of course has the disadvantage that the excess material must frequently be removed in additional steps and with other apparatus.
The most common alternative has been to design the articles so that they are free from overhanging portions. However, it is frequently desirable to mass produce articles with such overhangs and without coupling the articles together during molding either by strands, which are molded into the articles, or by ladder arrays of strips or the like.